The correlation between ultrasonography and histology in the search for gallstones

The majority of published data on the sensitivity and specificity of ultrasound in the diagnosis of gallbladder pathology was conducted over 30 years ago and, since the 1990s, ultrasound imaging has been the accepted gold standard. The quality and resolution of ultrasonography has improved significantly since then and we have, therefore, set out to assess whether the progression in technology has translated into improved diagnostic accuracy.

In the period December 2005 to December 2008, a total of 2100 patients underwent laparoscopic cholecystectomy for symptoms related to gallbladder disease. All patients underwent ultrasound examination prior to their surgery and histopathological analysis of their gallbladder postoperatively. We undertook a retrospective analysis of these patients comparing their pre-operative ultrasound scan and their histopathology report for the presence or absence of gallstones. Ultrasound scans were performed by a combination of radiologists and ultrasonographers.

The study identified a sensitivity of 0.85 and a specificity of 1 for ultrasound in the identification of gallstones. We found a sensitivity of 0.84 and 0.83 for the radiologists and ultrasonographers, respectively.

This study suggests that, despite an evolution in the resolution of ultrasound imaging, there has not been a corresponding improvement in sensitivity. There is a false positive rate of 16% which remains unchanged since the early 1990s.